Lockstitch sewing machine



LOCKSTITCH SEWING MACHINE Filed Sept. 18, 1940 2 Sheets-Sheet l 7 1/ nfor Witness I J ,2 (g I Feb. 24, 1942. J QLIVER 2,274,429

LOCKSTITGH SEWING MACHINE Filed Sept, 18, 1940 2 Sheets-Sheet 2 Patented Feb. 24, 19 42 UNITED! STATES PATENT OFF-ICE LOCIQSTITCH SEWING MACHINE John R. Oliver, Beverly, Mass., assignor to United Shoe Machinery Corporation, Borough of Flemington,- N. J.,,a corporation of New Jersey Application September 18, 1940, Serial No. 357,188

13 Claims.

The present invention relates to. lockstltch sewing machines and'is hereinafter illustrated as embodiedvin alockstitch shoesewing machine having acurved hook needle and a loopz taker of the rotary hook type in which each loop of needle thread is carried about a thread case without passing entirely about the loop taker.

In constructing a lockstitch hook needle sewing machine in which the loop taker is in the form of.a rotary hook, it is desirable in order to insure uniform passage of each needle loop over the thread case to maintain the thread case stationary and prevent its rotation with the loop taker. In the sewing machine illustrated and described in U; S. Letters Patent to Ashworth No. 1-,169,909 of February '1, 1916,a rotary hook type loop taker is provided and. a thread case which renders successive stitching operations .more uniform and the movements of the needle ducing noise and vibration in the machine and loops more regular as they are carried locking thread case.

With these and other objects in view, the present invention relates toa locking thread case about the retainer for preventing rotation of the thread supported in the loop taker is prevented fromrotation with the loop taker by a pair of reciprocating pins alternately engaging notches in one edge of a circular side wallof the thread case. These reciprocating pins frequently become worn and are generally a source of vibration. As a result of wear and vibration, the re ciprocating pins require frequent replacement and adjustment. Attempts heretofore have been case with the loop taker in a .lockstitch shoe sewing machine comprising a continuously rotating thread case engaging member arranged to permitpassage of each needle loop between the thread case and the retainer. The retainer member is formed with an interrupted circular surface so constructed that one end or the other of the interrupted surface remains in engagement with the thread case at all times.

In the machine in which the present inven-' tion is illustrated as embodied, the rotary loop taker is driven at a suiliciently rapid rate to insure passage of the needle loop about the thread case in time to complete the formation of a stitch within each sewing cycle and according to this feature of the invention, the retainer made to. avoid the use of reciprocating pins by substituting therefor an oscillating or reciproe eating thread case retainer member actuated positivelyby suitable mechanism in two directions,

first in one direction to permit passage of the needle thread between the thread case and the I member and then in the other direction to return the member to the original starting position. Such arrangements are .subject to the difficulty that when the retainer memberis actuated posiprevent the parts from becoming jammed and to tively in twmdirections, there is no opportunity for the thread case or.retainer member to yield in case the thread becomes jammed between the moving parts of the loop taker, thread case or retainer member. Thus, there is danger of structural injury of the parts.

The object of the present invention istoprovide a lockstitch shoe sewing machine of the type referred to in which the above difliculties are avoided and in which the use of a reciproeating or oscillating thread case retainer member is-eliminated. Other objects of the invention are to provide a noveland improved form of thread case retainer member with which proper operation is insured even after the bearingisurfaces of the parts become worn through long" continued operation. Still further objects are to 4 provide a thread case retainer member for use on this type of machine which is effective intreon the retainer member engages the thread case.

The retainer member, in .the present form of this feature,' is provided with a flange engaging an arcuate groove in the end wall of the thread case.

As the retainer member and loop taker rotate,

particles of stranded thread or wax may collect between the bearing surfaces of the parts. To

eject thread caught between the flange and groove in the thread case and retainer member,

respectively, thread ejecting recesses are provided in the engaging surfaces of either-or both the flange and groove. Preferably, the flange on the retainer member is. constructed to yield so as to admit thread within the groove without cuttingthe thread or causing breakage in the parts. As hereinafter illustrated and described, the flange is constructed in the form of indi-' vidual spring-pressed. slides urged yieldingly' against the surfaces of .the groove in the thread case.

While the features of the invention are par-. ticularly applicable to a lockstitch shoe sewing machine having a rotary hook and a thread case formed with an end -wall exposed at one side ofthe rotary hook, certain features also may be used to advantage with a sewing machine having 2 a true shuttle type of loop taker in which both the loop taker and thread case pass bodily through each needle loop.

These and other features of the invention and the advantages to be'obtained thereby will readily be understood by those skilled in the art from the following description taken in connection and the thread case; Fig. 3 is a similar view illus-- trating the operation just as a needle loop is being cast off the thread case by the loop taker; Fig. 4 is a view similar to that illustrated in Fig. 2 of a thread case retainer member of the same form of construction and mode of operation as illustrated in Figs. 1 to 3, but employed with a rotary loop taker of the shuttle type in which the loop taker, together with the thread case, passes through each needle loop; Fig. 5 is a side view of the parts illustrated in Fig. 4; Fig. 6 is a detail sectional view, on a slightly reduced scale, of the groove and thread ejecting recess forward leg of the needle loop has been carried about the thread case, the passage of the thread case through the loop will be completed. To hold the thread case from rotating with the loop taker so that the rearward leg of the needle loop will not be carried about the thread case with the forward leg, thus causing the thread to become entangled with the loop taker in the machine of the patent, there are a pair of pins mounted for reciprocation in a cover for the loop taker corresponding to the cover indicated in Fig. 1 of the present drawings by the numeral 28 and a spring also mounted on the cover acts to maintain these pins in notches formed at the upper edge of the circular side thread case wall.

The inner surface of the loop taker is provided with a cam which acts to raise these pins alternately during passage of each needle loop about the thread case. The action of the'cam and the pins during rapid operation of the machine causes a series of impacts between the parts and forms a source of undesirable vibration in the machine.

The means for retaining the thread case from rotation with the loop taker, in the machine of the present invention comprises a continuously rotating circular member having an interformed in the end wall of the thread case; Fig. '7

is a detail view, on an enlarged scale, of a modified form of thread case retainer member having a yielding flange; Fig. 8 is a sectional view of the thread case retainer member illustrated in Fig. '7; and Fig. 9 is a detail view, on a further enlarged scale, of one of the flanged elements in the retainer member illustrated in Figs. '7 and 8.

The machine illustrated in the drawings has substantially the same stitch forming devices and actuating mechanisms, except as hereinafter illustrated, as the machine disclosed in the patent to Ashworth above referred to, or in the present inventors Patent No. 1,950.564 of March 13, 1934. The illustrated machine is provided with a curved hook needle 2, a curved awl 4, a work support '6, a presser foot 8,, a rotary type loop taker ill, a locking thread case l2, loop spreader l4, and other devices and mechanisms for actuating the same. The actuating mechanisms are driven from the main'sewing shaft l6 having suitable cams, cranks and gears to provide the proper operations of the stitch forming devices. As in the machineof the Ashworth patent, the loop taker of the illustrated machine is driven through three complete rotations during each single rotation of the sewing shaft l6 by means of a beveled gear l8 on the sewing shaft, and a smaller beveled gear 20 secured to the rearward end of a short loop taker drive shaft 22, the forward end of which has a beveled gear 24 meshing with gear teeth formed on the loop taker Ill. The loop taker is constructed with a supporting raceway 25 into which fits the inner surfaces of stationary arcuate plateson the machine frame and with a circular guideway 26 within which a peripheral flange on a cylindrical side wall of the thread case l2 slides. The operation of the loop' taker is such that after each loop of needle thread is drawn through a perforation formed by the aw'l in the work and is spread by the spreader H, as illustrated in Fig. 1, the beak of the loop taker enters the spread loop, causing the forward leg of the loop to be carried about the thread case, the rearward. leg being disengaged from the needle and held by the thread case from rotation with the loop taker. Thus, after the rupted circular surface formed by a flange portion extending from the periphery of the member in the direction of the axis about which said member rotates and engaging an arcuate groove 32 (see Fig. 2) in the rear end wall of the thread case. The surfaces of the groove 32 are curved to fit the surfaces of the flange portion of the retainer member and the groove is so located that its center of curvature coincides with the rotary axis of theretainer member. 'The rotary axis of the retainer member is arranged in parallel relation with, but eccentric to, the rotary axis of the loop taker. so that the groove 32 covers only a fractional part of the thread case end wall. The interrupted flange portion of the retainer member is of such length that the trailing end of the flange does not become disengaged from the groove 32 before the leading end of the flange enters the groove. The rotation of the retainer member is so timed with relation to the rotation of the loop taker, as indicated by the arrows, that the thread of the needle loop passes between the ends of the flange portion on the member 30 is given a single complete rotation foreach three rotations of the loop taker.

To drive the retainer member, the loop taker drive shaft 22 has secured between its ends a bevel gear 34 meshing with a corresponding gear 36 on an inclined shaft 38. The shaft 38 also carries a bevel gear 40 meshing with bevel gear teeth 42 on the periphery of the retainer member, the retainer member being secured to a stub shaft 44 rotating in a bearing bracket 46 mounted on the frame of the machine.

As each needle loop is being carried over the top of the thread case, as indicated in Fig. 2, there may be a tendency for the movement of thread to be retarded by misplacement into the groove 32. According to the present construction, if (the thread of the needle loop is so retarded that it becomes caught between the sides of the groove 32 and theleading edge of the flange on the retainer member or becomes stranded through contact either ,with the groove or the retainer member so that fibers or particles the machine in the same manner asthe rotary .hook .type loop taker l0. The loop taker 51 is of wax becomeuembedded in the groove 32, the

groove will be cleared during rotation of the retainer member by thread ejecting recesses 41 and 48 formed in the side walls of the groove 32 and the surfaces of the flange on the retainer memher. The -recess 41 is inclined from the bottom of the groove outwardly towards the surface of:

the thread case'and' the recess 48 in the retainer member is inclined from the outer edge of the flange on the retainer member downwardly to draw foreign materials from the groove towards the surface of the thread case wall. The depth of the recess is such as to accommodate the thickness of the thread so as to'reduce the possi-- bility of-cutting or otherwise injuring the thread caught within the recess.

As a still further means for reducing the tendency to injure misplaced threads caught between the groove of the thread casev and the retainer member, as well as to permit free rotation of the parts if the thread case becomes jammed within itsguideway in the loop taker, the flange portion of the retainer may be constructede illustrated in Figs. '7 and 8 with a series of individual slides v 49 having T-shaped portions engaging correspondingly shaped guideways disposed parallel to the axis about which the retainer member rotates. Each slide 49 is formed with an elemental wedge-shaped flange portion and a slot 50. through which passes a'pin 52- for. securing the .slide in place on the retainer member. The main body of the retainer member, when provided with individual slides, is indicated at 54 and the pins formed with a supporting raceway 58, a beak 60 at one end of a flange extending nearly around the periphery of the loop taker, and gear teeth 62 out in the periphery of the loop taker, which gear teeth mesh with suitably formed teeth on I the driving gear 24. With the use of the shuttle type loop taker 51, a thread case 64 is rotatably supported within the loop taker and the lower end wall of the thread case is provided with a groove 66 corresponding with the groove 32 in the thread case I2. The movements of the rearward leg of the needle thread loop with the use of the loop taker 51 is substantially the same as the movements of the forward leg of the needle thread loop during rotatibn of a rotary hook type loop taker. The forward leg of the needle loop when using the shuttle type loop taker 51 is illustrated in Fig. 5 indicating its movement across the forward open end of the thread case and the forward end of the shuttle. Otherwise the operation of the two types of'loop taker is similar and consequently is not retarded by the thread case 52 are driven into radial openings formed in the body 54. To force the flange portions of the slides towards the thread case and to permit the slides to yield in case the groove 32 becomes filled withforeign material, a coil spring 56 is compressed between an indentation within one end of the slot and a flat surface near the! outer end of each pin 52. There area sumcient number of slides 42 to cover the same angle about the periphery of .the retainer member '54, as is covered by the flange portion of the retainer retainer illustrated.

The nature and scope of the invention having beenv indicated and a particular embodiment thereof having been illustrated and particularly described, what is claimed is:

v 1. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a locking thread case, a rotary loop taker in which the locking thread case is supported,

means fordriving the loop taker' to carry each loop of needle thread about the thread case, and means for retaining thethread case from rotation with the loop taker comprising a continuously rotating thread case engaging memating surfaces on the thread case to permit pas- ,sageof eachneedle loop between the thread case r and the rotating .member while one end or the member illustrated in Figs. 2 and 3. By provlding a. suitable number of slides, the thread case is held from rotation with the loop taker by two or more slides-at all times except momentarily ust before the leading slide 48 on the retainer member enters the groove 32 and just after the trailing slideleaves the groove 32,. Thus, a reliable control of the thread case is obtained. If

other of the interrupted surface remains in engagement with the thread case. y

3. A lockstitch sewing machine having, incombination, stitch forming devices including a hook needle, a locking thread case, a rotary loop taker in which the locking thread case is supported,

there is anysubstantial-strain during the time 'the leading or trailing slides alone hold the thread case from rotation, th'se slides may be. wedged from within the groove 32 in'the thread case and the thread case allowed-to rotate with the loop taker. No serious structural injury to the machine will occur when this takes place, due 'to the yielding action and the shape of the slides.

' Referring to Figs. 4 and 5, the r tainer memher is illustrated as applied v.to a achine' having a rotary loop taker of the shuttle type in which means for driving the loop taker continuously to carry each loop of needle thread about the thread case, means for retaining" the threadv case from rotation with the loop taker comprising a continuously rotating member formed with an interrupted circular surface engaging cooperating surfaces on the'thread case to permit passage of each needle loop between the thread case and the rotating member while the interrupted surface remains in engagement with the thread case, and

both theloop taker and thread case pass bodily through each needle loop. According to the construction illustrated, the shuttle type loop takerv is indicated at El and is mounted for rotation in means for driving the rotating member at a speed slower than that of the loop taker to cause pas- ,sage of the needle loop about the thread case to be completed while the interrupted circular surface on the rotating member engages the thread case.

I taker comprising a member formed with an interrupted circular surface engaging cooperating surfaces on the thread case to permit passage of each needle loop between the thread case and the rotating member, and driving connections between the drive shaft for the loop taker and the thread case retainer member.

5. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a locking thread case, a rotary loop taker which-the locking thread case is supported, a drive shaft, a gear on the drive shaft meshing with gear teeth on the loop taker, means for retaining the thread case from rotating with the loop taker comprising a rotary member formed with an interrupted circular surface engaging cooperating surfaces on the thread case to permit 1 passage of each needle loop between the thread case and the rotating member, a second gear on the drive shaft, and 'a gear driven from said sec- 0nd gear and meshing with .gear teeth on the thread case retainer member to rotate the retainer member in timed relation with the loop taker. i

6. A lockstitch sewing machine having, in combination, stitch forming devices including a hook needle, a locking thread case, a rotary loop taker in which the locking thread case is supported, means for driving the loop taker to carry each needle loop about the threadcase, and a thread case engaging member rotated continuously in a direction opposite to the direction of rotation of the loop taker in carrying the'needle' loop about the thread case to retain the thread case from rotation with the loop taker.

7. A lockstitch sewing machine having, in combination, stitch forming devices including a hook for driving the loop taker to carry each loop of needle threadabout the thread case, a discoidal -rotary member having an interrupted flange extending axially from its periphery and engaging the groove in the end wall of th thread case to retain the thread case from rotation with the loop taker, and recesses in the engaging surfaces of the flange and groove for ejecting thread caught between the flange and groove during pasv sage of the needle loop over the thread case.

10. A lockstitch sewing machine having, in combination, stitch forming devices including a curved hook needle, a locking thread case having a cylindrical side wall and a grooved end wall, a rotary loop takerin which the locking thread case is supported, means for driving the loop taker to carry each loop of needle thread about the thread case, a rotary thread case retainer member, and a yielding flange on the retainer member engaging the groove in the end wall of the thread case to admit passage of thread through the groove without cutting' the thread.

11. A lockstitch sewing machine having, in combination, stitch forming devices including a curved hook'needle, a locking thread case having a cylindrical side wall and a grooved end wall, a rotary loop taker in which the locking thread case is supported, means for driving the loop taker to carry each loop of needle thread about the thread case, a rotary thread case retainer member, and a series of slides having flanged portions mounted for movement on the retainer member towards and from the groove in the thread case to admit passage of thread through the groove as the loop taken carries the needle thread about the thread case.

12. A lockstitch sewing machine having, in combination, stitch forming devices including a curved hook needle, a locking thread case having needle, a locking thread case, a, rotary loop taker in which the locking thread case is' supported, means for driving the loop taker to carry each loop of needle thread, about the thread case, and means for retaining the thread case from rotation with the loop taker comprising a circular rotary member. formed with a flange extending axially from the peripheryof said member and 1 engaging arcuate surfaces on the thread case.

8. A lockstitch sewing machine having, in com-' bination, stitch forming devices including a curved hook needle, a locking thread case having a cylindrical side wall and amend wall formed with an arcuate groove, a rotary loop taker in which the locking thread case is supported, means for driving the loop takerto .carry each loop of needle thread about the thread case, and a discoidal member arranged to rotate about an axis eccentric to the rotary axis of the loop-taker and provided with a flange engaging the arcuate groove in the end wall of the thread case to retain the threadca'se from rotation with the loop taker.

9. A lockstitch sewing machine having, in combination,- stitch forming devices including a a cylindrical'side wall and a grooved end wall,

a rotary loop taker in which the locking thread case is supported, means for driving the loop taker to carry each loop of needle thread about the threadcase, arotary thread case retainer member, a series of slides having flanged portions mounted in guideways in the retaining member,

and individual resilient elements acting on the slides to press the flanged portions into the groove of the thread case to admit passage of thread through the groove as the loop taker carries the needle thread. about the thread case.

13. A lockstitch sewing/ machine having, in

1 combination, stitching forming devices includingv a curved hook needle, a locking thread case havinga cylindrical side wall and a grooved end wall,, a rotary loop taker in which the locking thread case is supported, means for. driving the loop taker to carry ach loop of needle thread about the thread case, a rotary thread case retainer member, a series of slides having flanged portions mounted in guideways in the retaining to form an interrupted circular surface, the

curved hook needle, a locking thread case having a cylindrical side wall and an end wall formed with an arcuate groove, a rotary loop taker in which the locking thread case is supported, means member, and individual resilient elements acting onthe slides to press the flanged portions into the groove of'the thread case to admit passage of thread through the groove as the loop taker carries the needle thread about the thread case, the flanged portions of said slides being arranged length of which is suflicient to prevent disen-- gagement from the thread casein any position of the retainer member during rotation.

JOHN R. OLIVER. 

